The present disclosure relates to power devices and, more particularly, to secondary power devices that secondarily supply power, and to memory systems including the secondary power devices. In general, a memory system including memory devices and a memory controller operates by receiving power from an external source. In this regard, a sudden power off (SPO) situation in which the power (e.g., main/primary power) is suddenly discontinued while the memory system operates may occur. In this case, because the memory controller may store data by using a volatile memory, the data stored in the volatile memory may be at risk of being lost and/or a memory device may be at risk of not completing its operation (e.g., an erase operation, a write operation, etc.). Accordingly, in response to an SPO situation, the memory system may attempt to complete an ongoing operation by using a secondary power device, and/or may perform an operation of backing up the data. Moreover, it may be desirable to verify the health of the secondary power device, to ensure that it is capable of adequately providing power.